Optical scanning and imaging applications often use mirrors to control the focus, trajectory, and shape of reflected light. For instance, bar code scanners commonly use mirrors to focus a laser beam on a bar code and to move (i.e., scan) the laser beam back and forth across the bar code. Similarly, imagers such as optical scanners and photocopiers commonly use mirrors to focus light on objects being imaged and to control a scanning path of the focused light along these objects.
In many optical scanning and imaging applications, light is generated by a collimated light source such as a laser. A collimated light source generates a column of light (also called a “collimated beam”) where each ray of light has a trajectory that substantially parallels the trajectories of other rays of light in the column. In practice, light diffraction makes it difficult to create a perfectly collimated beam, i.e., a beam where each ray of light exactly parallels every other ray of light. Accordingly, the light diffraction in a collimated beam creates a need for mirrors to shape, focus, and steer collimated beams in various optical scanning and imaging applications.
As an example, when a bar code scanner directs a laser beam at a bar code, diffraction may cause the laser beam to appear on the bar code as a larger or smaller laser spot depending on the distance between the bar code scanner and the bar code. If the laser spot on the bar code is larger than the bars of the bar code, the bar code reader may be unable to properly read the bar code. Accordingly, the bar code scanners may be designed to focus light at a small point within a fixed distance of the scanner for a given sized bar code; however, outside the range, the scanner may be unreliable.
Different types of mirrors can be used to manipulate light in different ways. As examples, a parabolic mirror can be used to focus light into a small spot, or cylindrical mirror can be used to create an elongated light beam from a reflected beam. These and other types of mirrors can manipulate light in the form of beams and other forms. Similarly, various techniques can be used to steer light in different directions. For instance, bar code scanners often use oscillating mirrors to move light back and forth and telescopes and microscopes commonly use movable mirrors to vary the magnification of objects being viewed.
Most conventional mirrors for manipulating light have only one configuration, and therefore they generally are only able to focus, steer, or shape light in one particular way. For instance, most parabolic mirrors only provide one level of focus and most cylindrical mirrors provide a single type of reshaping. However, in some applications, it may be advantageous to use mirrors capable of performing different types of manipulations. Among these applications, there are size-limited or cost limited components that need to perform multiple light manipulations, but would be too large or expensive if implemented with multiple mirror components.
In order to vary the way in which light is manipulated by a single mirror, researchers have developed techniques whereby a single deformable mirror performs multiple different types of light manipulations based on its configuration. For the most part, these conventional deformable mirrors change configuration under the control of mechanical components. For instance, some applications have used micro-electro-mechanical systems (MeMs) to control mirror deformations.
Unfortunately, these mechanical components tend to be somewhat unreliable and costly. Additionally, the operation of these components typically consumes a significant amount of power, requires complex control mechanisms, and provides inaccurate movements. Accordingly, their utility can be limited by these and other factors.
In view of the above shortcomings, a need exists for improved techniques and technologies for performing mirror deformations in a variety of different applications. The above examples of prior systems and their associated limitations are intended to be illustrative and not exclusive. Other limitations of existing or prior systems will become apparent to those of skill in the art upon reading the following.